Background: Breast cancer is the most frequent cancer in women. Green tea has been studied
for breast cancer chemopreventive and possibly chemotherapeutic effects due to its high content in
polyphenolic compounds, including epigallocatechin-3-gallate (EGCG).
Method: This review is based on literature research that included papers registered on the Medline®
database. The research was conducted through PubMed, applying the following query: “EGCG”AND
"breast cancer”. The result was a total of 88 articles in which this review stands on.
Results: In vitro, EGCG shows antioxidant or pro-oxidant properties, depending on the concentration
and exposure time. EGCG blocks cell cycle progression and modulates signaling pathways that affect
cell proliferation and differentiation. EGCG also induces apoptosis, negatively modulates different
steps involved in metastasis, and targets angiogenesis by inhibiting VEGF transcription. In vivo investigations
have shown that oral administration of EGCG results in the reduction of tumor growth and in
antimetastatic and antiangiogenic effects in animal xenograft and allograft models.
Discussion: Much remains unknown about the molecular mechanisms involved in the protective effects
of EGCG on mammary carcinogenesis. In addition, more studies in vivo are necessary to determine
the potential toxicity of EGCG at higher doses and to elucidate its interactions with other drugs.
Conclusion: A protective effect of EGCG has been shown in different experimental models and under
different experimental conditions, suggesting clinical implications of EGCG for breast cancer prevention
and therapy. The data presented in this review support the importance of further investigations.